Manufacture of artificial stone.



P TENTBD MAR.10,1903.

VEN TIF 1. BENBWED C. W. STE MANUFAGTURE 0F AR APPLIOATION FILED APB. 6, 19o

STNE.

MNHN

CHARLES W. STEVENS,

Turcs.

ATENT OF HARVEY, ILLINOIS.

MANUFACTURE OF ARTIFICIAL STONE.

SPECIFICATION forming part of Letters Patent N o. 722,464, dated March 10, 1903.

Application filed April 6, 1901. Renewed January 2, 1903. Serial No. 137,572. (No model.)

ture of articles from artificial stone generally;

but in the manufacture particularly of sewerpipes from artificial stone difficulty has been experienced in insuring against the presence of air-bubbles. Consequently in the manufacture of such articles as a general practice the stone material is tamped or driven into a mold. By my invention I obviate the necessity of tamping and am enabled to make the` article successfully by pouring the mixture into the mold and at the same time to insure results equal to those obtained by the `more expensive and tedious processes. Moreover, in the manufacture of such articles by processes in which tamping is employed there is diflculty experienced in securing uniformity of density, an objection obviated by my process.

In the accompanying drawing I illustrate a central. vertical section of one form of apparatus adapted to carry out my process in the manufacture of sewer-pipes.

Referring to the numerals on the drawing, 1 indicates the case or outer shell of a mold provided with a closed bottom 2, attached thereto.

3 indicates a core, which may be made of any suitable material, extending from the bottom and deuing between it and the shell the mold-cavity, which in the form illustrated is adapted to mold a section of sewer-pipe.

4 indicates a ring which, surrounding the lower end ofthe core 3, is adapted to form the joint-flange on the pipe.

The case l is closed by a removable lid 5, which may be provided with a rubber or other gasket 6 for forming an air-tight joint lbetween the lid and the case. In the upper part '7, having a fora'minous or perforated bottom 8. The tray fits the upper end of the moldcavity and is adapted to support therein a layer of porous or permeable material, preferably sand.

9 indicates a supply-pipe which, entering the mold-cavity below the tray, is adapted to supply by an air-tight connection a stone mixture in a liquid state to the interior of the mold. This stone mixture may be of any preferred kind, consisting, for example, of cement, sand, slag, or ground stone, with sufficient water to render it iuid and with any coloring-matter or other material which may be desired.

lO indicates an air-exhaust pipe which communicates with the mold-cavity, preferably above the tray, and being connected with air-pumping mechanism on the outside of the case is adapted to produ/ce a partial vacuum Within the mold-cavity. The pipe l0 may also be employed to carry off with the air such superfluous water as may accumulate above the tray, the tray acting as a strainer for the separation of the water from the solid particles contained therein.

In carrying out my process the parts being 4properly assembled and the lid 5 being closed and secured against its gasket 6 the air is vpreferably first' exhausted from the mold.

Then afterward the stone mixture is supplied to the mold through the pipe 9, the air being kept pumped out While the mold is being filled.

The pumping out of the air ahead of the incoming stone mixture insures the proper lling of the mold and the absence of air-bubbles. This in 1tself tends to render the stone. formed in the mold of uniform density; but.

in addition to that provision is made in the presence of the tray with its porous contents for securing the same result, the operation being as follows: As the mold-cavity fills with the stone mixture its level within the cavity rises until it reaches the foraminous bottom of the tray, of the tray permit the passage through it of the superliuous water inthe stone mixture, but retains its solid constituents within the cavity. In other words, the porous contents of the tray act as a strainer, so that the moldof' the v'easel I provide an annular tray when the porous contents ICO cavity will be completely and uniformly filled with the stone mixture of equal density, the Water which holds the mixture in solution passing off through the tray, and thence through the pipe 10.

For some purposes the case l or the core 3, or both, might be made of or lined with sand, in which event it would be sufficient to employ means for pumping out the air ahead of the supply of stone mixture Without employing the strainer, although the strainer might still be used, if desired. For other purposes the strainer might be employed advantageously 'without pumping out the air. It would therefore appear that while my `process contemplates the simultaneous exhaust of air and the forcing of the mixture against a strainer, yet it is obvious that those two features of my present invention may be employed independently to advantage under certain circumstances.

What I claim is- 1. An improvement in the manufacture of artificial stone, which consists in forcing a stone mixture in a liquid state into a closed .mold provided with a permeable Wall, Whereby the liquid portion of the mixture is forced CHARLES W. STEVENS.

Witnesses:

CEAS. E. RIORDON, KARL J. DANIEL. 

